add particle effect global function, arrow lifetime, api.txt update

api.lua

@@ -6,7 +6,7 @@ local use_cmi = minetest.global_exists("cmi")
 
 mobs = {
 	mod = "redo",
-	version = "20200619",
+	version = "20200620",
 	intllib = S,
 	invis = minetest.global_exists("invisibility") and invisibility or {}
 }
@@ -645,7 +645,14 @@ local effect = function(pos, amount, texture, min_size, max_size,
 	max_size = max_size or 1
 	gravity = gravity or -10
 	glow = glow or 0
-	fall = fall and 0 or -radius
+
+	if fall == true then
+		fall = 0
+	elseif fall == false then
+		fall = radius
+	else
+		fall = -radius
+	end
 
 	minetest.add_particlespawner({
 		amount = amount,
@@ -665,6 +672,12 @@ local effect = function(pos, amount, texture, min_size, max_size,
 	})
 end
 
+function mobs:effect(pos, amount, texture, min_size, max_size,
+		radius, gravity, glow, fall)
+
+	effect(pos, amount, texture, min_size, max_size, radius, gravity, glow, fall)
+end
+
 
 -- update nametag colour
 function mob_class:update_tag()
@@ -3862,6 +3875,7 @@ function mobs:register_arrow(name, def)
 		drop = def.drop or false, -- drops arrow as registered item when true
 		collisionbox = def.collisionbox or {-.1, -.1, -.1, .1, .1, .1},
 		timer = 0,
+		lifetime = def.lifetime or 4.5,
 		switch = 0,
 		owner_id = def.owner_id,
 		rotate = def.rotate,
@@ -3876,11 +3890,11 @@ function mobs:register_arrow(name, def)
 
 		on_step = def.on_step or function(self, dtime)
 
-			self.timer = self.timer + 1
+			self.timer = self.timer + dtime
 
 			local pos = self.object:get_pos()
 
-			if self.switch == 0 or self.timer > 150 then
+			if self.switch == 0 or self.timer > self.lifetime then
 
 				self.object:remove() ; -- print("removed arrow")
 

api.txt

@@ -293,7 +293,8 @@ enhance mob functionality and have them do many interesting things:
    'custom_attack'  when set this function is called instead of the normal mob
                     melee attack, parameters are (self, to_attack) and if true
                     is returned normal attack function continued.
-   'on_die'         a function that is called when mob is killed (self, pos)
+   'on_die'         a function that is called when mob is killed (self, pos), also
+                    has access to self.cause_of_death table.
    'do_custom'      a custom function that is called every tick while mob is
                     active and which has access to all of the self.* variables
                     e.g. (self.health for health or self.standing_in for node
@@ -387,6 +388,24 @@ true the mob will not spawn.
     'name'   is the name of the animal/monster
 
 
+Particle Effects
+----------------
+
+mobs:effect(pos, amount, texture, min_size, max_size, radius, gravity, glow, fall)
+
+This function provides a quick way to spawn particles as an effect.
+
+    'pos'       center position of particle effect.
+    'amount'    how many particles.
+    'texture'   texture filename to use for effect.
+    'min_size'  smallest particle size.
+    'max_size'  largest particle size.
+    'radius'    how far particles spread outward from center.
+    'gravity'   gravity applied to particles once they spawn.
+    'glow'      number between 1 and 15 for glowing particles.
+    'fall'      when true particles fall, false has them rising, nil has them scatter.
+
+
 Making Arrows
 -------------
 
@@ -422,7 +441,9 @@ This function registers a arrow for mobs with the attack type shoot.
        'on_step'      is a custom function when arrow is active, nil for
                       default.
        'on_punch'     is a custom function when arrow is punched, nil by default
-       'collisionbox' is hitbox table for arrow, {0,0,0,0,0,0} by default.
+       'collisionbox' is hitbox table for arrow, {-.1,-.1,-.1,.1,.1,.1} by default.
+       'lifetime'     contains float value for how many seconds arrow exists in
+                      world before being removed (default is 4.5 seconds).
 
 
 Spawn Eggs